Motor control apparatus



Oct. 17, 1933. c w DALZELL v 1,930,950

MOTOR CONTROL APPARATUS Filed July 20, 1931 BH J g-j Ii 7 15 -fir-CH BHJc iQ C CHJJ i 2 INVENTOR.

C,W. Dar/22,

Patented Oct. 17, 1933 breaker actuated by the motor controlling con-1MoToR CONTROL APPARATUS Clarence W. Dalzell, Swissvale, Pa., assignor toThe Union Switch & Signal Compamuswiss vale, Pa acorporation ofPennsylvania ]inp li0ation July 20, 1931. Serial No.'551,S59- rema ns.(c1. 175 294) .My invention relates to motor control apparatus, andparticularly to apparatus'lforv controlling a railway switch operatingmotor from a distant point suchas an interlocking tower or despatcherscabin. I a 1 1 One object-of my invention is to decrease the amount ofpower which it'is necessary to transmit from thecontrol location to themotor controlling contactor, and I accomplish thisresult by eliminatingthe usual form of overload circuit tactor and by substituting therefor athermal overload-relay cooperating with'a locallyenergized controllingmagnet applied to the motor circuit in a novel manner. a i

. Another object of-my invention is'to provide a thermal overload relaycapable of being reset electrically after a very short cooling time.

A further object is to provide a flexible and reliable motor controlandoperating circuit for the safe and eiiicient operation of an outlyingrailwayswitch.

' -I will describe'one form of 'apparatus embodying my. invention, andwill then novel features thereof in claims.

point out the The accompanying drawing is a diagrammatic view showingone form of apparatus embodying my invention.

here shown comprises an armature 1 and a field 2. Operatively connectedwiththe switch A is a cut-out controller D comprising an arm 3 andcontact segments 4 and 5. Contact 3-4 is closed at all ltimes exceptwhen the switch occupies its extreme normal position, and .contact 3-5is closed-at all times except when the switch occupies its extreme:reverse position.

' The motor M is controlled by a polarized motor controller? which inturn is controlled by a manually operable pole-changer Lusually locatedat a point remote'from the controller P. .The

tacts on a manually operable switch lever.

Polarized controller P comprises an armature 9; pivoted upon a pin 10mounted in the polarized core 11 and capable of being attracted toeither one or the other of neutral cores 12 or 13 depending upon thepolarity of the currentflowing in the series windings 14 and 15 asdeterminedby the position of pole-changer L, provided polarizing winding53 on core 11 is energized at the same time. .Armature 9 of controller?operates contact arms'6 and 7 which act to close .contacts which will beexplained hereinafter.

pole-changerL mayconsistof pole-changing con- 6-16 and 7-17 when thearmature assumes the position shown in the drawing, and to closecontacts 6-18 and 7-19 when the armature is reversed. Contact arms 6 and7 serve asameans for reversing the direction of current flow through thearmature 1 of motor M without influencing.

the direction of current now through the field Winding 2. The positionof armature -9 determines therefore whether normal or reverse rota-jtion of motor M will follow,resulting in switch A assuming itscorresponding normal or reverse position. yv i Armature 9 also operatescontact arm 8 to close contacts 8-20 or 8-21 which permit relay E tobecome energized. Relay E provides'a means for resetting thermaloverloadrelay T; and opcrates contact fingers -22 and23,-the purpose of Relay Ecomprises a winding 27 capable-of attracting an armature 28 pivotedat'29. 'A pin 30 provides a stopfor armature 28 when winding 27' iS-deenergized. r

Thermal overload relay T'comprises two bimetallic strips-31 and 32fastened to a supporting block 33 and joined'together at their free endsbyja link 34. The-bimetallic strips 31'and32 are so disposed withrespect to each other that a U i change in ambient temperature willcause said 1 Referring to the drawing, the reference char-- acter Adesignates a railway switch which is actu-' ated by'an electric motor Mwhich in the formstrips to tend todeiiect in opposite directions; withthe result that no'appreciable movementof roller 35Vattachedto strip 31occurs until. winding 36 becomes heated. Compensation for'ambienttemperature is obtained in this'manner; I

causes .armature 23 tolift arm 37 through'the medium of slotted link'41. a

Magnet F comprises two windings 42 and 43} wound in opposition to eachother and connected in series acrossthe motor armature. The circuit forwindings 42 and 43 is so arranged that when contact 38-39 ofthermal-overload relay T is closed, these windings are in parallel witheach other and the current now througheach winding is in'such directionthat the resultant fluxes-and,-

causing'magnet F to pickup, opening contact 44-45 and closing contact46-47. When, however, contact 38-39 becomesopened for anyreason, currentflows in series through windings 42 and 43 so that the fluxes opposeeach other and magnet F releases, opening contact 46-47 and closingcontact 44-45.

In order to explain the operation of the apparatus as a whole, I shallassume that the operator wishes to reverse switch A from the normalposition shown in the drawing. To do this, he reverses pole-changer L,establishing a circuit for relay E from one terminal BH of the source,arm 48 of pole-changer L, wire 50, wire 51, con tact 8-20, wire 52, andwinding 27 of relay E to the other terminal CH of the source. Relay Enow becomes energized, opening contact 22-24 and closing contacts 22-25and 23-26. The closing of contact 22-25 establishes a circuit forpolarizing winding 53 of controller P, starting at terminal BH, winding53, wire 54, and contact 22-25 to the other terminal CH of the source.Contact 23-26 closes a circuit for windings l4 and 15 of controller Pwhich can be traced from terminal BH, arm 48 of pole-changer L, wire 50,wire 55, contact 44-45 of magnet F, wire 56, contact 23-26 of relay E,wire 57, windings 15 and 14 of controller P, wire 58, wire 59, and arm 49 of pole-changer L to the other terminal CH of the source.

With the windings of controller P energized as above, armature 9 becomesattracted to core 13 and contact fingers 6, 7 and 3 become reversed fromthe position shown in the drawing. The opening of contact 8-20 causesrelay E to release, and the closing of contact 8-21 short circuits relayE and prepares an energizing circuit for relay E effective uponsubsequent reversal of pole-changer L. The release of relay E openscontacts 22-25 and 23-26 so that all windings on controller 1? becomedeenergized. The closing of contacts 6-18 and 7-19 energizes windings.42 and 43 of magnet F in parallel, the circuit for winding 43 startingat terminal BH, contact 3 5 of controller D, wire 60, contact 6-18, wire61, wire 62, winding 43 of magnet F, wire 63, wire 64, flexibleconnector 65, contact 88-39 of relay T, wire 66, and contact 22-24 ofrelay E to the other terminal CH of the source. The circuit for winding42 is the same as above except that at wire 61 it branches to includewire 67, armature l of motor M, wirev 68, wire 69, winding 42, wire 70,and thence through wire 64 over the same circuit just traced for winding43. It will be noted that under this condition winding 42 aids winding43 and the energy in winding 42 is nearly as great as in winding 43,being decreased only by the po 'tential drop across the armature 1 ofmotor M at standstill.

It will be apparent therefore that the combined effect of windings 42and 43 creates a strong pick-up impulse in magnet F, closing contact46-47 and opening contact 44-45.

When contact 46-47 is closed, a circuit for motor M is established whichcan be traced from terminal BH, contact 3-5 of controller D, wire 60,contact 6-18, wire 61, wire 67, armature 1, wire 68, wire 71, contact7-19, wire 72, wire 73,

held 2, wire 74, contact 46-47, wire 75, heatinsure that should lever Lbe reversed with magnet F energized and motor M operating, contact 46-47will become opened due to the establishment of the series connection forwindings 42 and 43 of magnet F by the opening of contact 22-24 of relayE, with the result that contact 46-47 will cut off motor current beforecontact 44-45 closes to energize windings 14 and 15 of controller P fora reversal of contacts 6 and 7, otherwise contacts 7-19 and 6-18 wouldbe required to break the motor current, for which service they have notbeen designed. When switch A reaches its extreme reverse position,contact 3-5 of controller D opens, deencrgizing motor M and magnet Allparts will then be deenergized.

Should the operator wish to restore switch A to the normal positionshown in the drawing, he will restore pole-changer L to the positionillustrated, whereupon the following sequence of operations, alreadydescribed in connection with the movement of switch A from normal toreverse will take place: Relay E will be energized, energizingcontroller P which will restore contact arms 6, 7 and 8 to the positionillustrated, resulting in deenergization of relay E which in turn causesmagnet F to become energized, deenergizing, controller P and energizingmotor M. The operating circuit for motor M can now be traced from oneterminal 13H, contact 3-4 of controller D, wire 77, contact 7-17, wire71, wire 68, armature 1, wire 67, wire 61, contact 6-16, wire 78, wire73, field 2, wire 74, contact 46-47, wire 75, heating winding 36, andwire 76 to the other terminal CH of the source. It will be noted thatthe direction of current flow through the motor armature has now beenreversed, the flow through the field Winding remaining in the samedirection as before, with the result that motor M will reverse itsdirection of rotation and will restore switch A to the normal positionin which it is shown. As soon as switch A reaches its normal position,contact 3-4 of controller D will open, deenergizing motor M and magnetF. All parts will then be restored to the positions in which they areillustrated.

Contacts 22-25 and 23-26 of relay E are necessary in order thatcontroller P may remain deenergized at all times except during the shortinterval required for reversing contact arms 6, 7 and 8. Contact 22-24of relay E is provided for the purpose of releasing magnet F shouldpolechanger L be reversed while the motor is operating. In this manner,contact 22-24 is instrumental in allowing full control over the motor Mto be maintained by pole-changer L during any part of the stroke ofswitch A, i. e. switch A can be brought back to its initial positionafter completing any part of its stroke by a reversal of pole-changer L.The sequence in which the elements operate to bring about a reversal ofswitch A in mid-stroke is the following: Reversal of polechangcr L,pick-up of relay E, release of magnet F, reversal of controller P,release of relay E, and finally pick up of magnet F which energizes themotor to operate switch A.

To explain the operation of the apparatus when motor M becomesoverloaded, caused for example by an obstruction in switch A, I shallassume that motor M is operating to reverse switch A from the normalposition shown in the drawing when such an obstruction occurs. Thecurrent taken by motor M will now increase and the heat developed inwinding 36 of relay T will cause bimetallic strip 31 to deflect totheright. Roller 35 will disengage arm 37 causing contact 38-39 to.open,

I 1,930,050 breaking the'paiallel connection for" windings 42 and 43 ofmagnetF and forcing the'current to fiow through both of these windingsin series, whereby opposing fluxes are created and magnet Freleases.

i The release of magnet'F .opens'contact 46-47 pole-changer L to theposition shown in the drawing, whereupon relay E will become energizedand will reset contact 38-39 which will now remain closedafter relay Eis subsequently deenergized because of the engagement of roller 35 witharm 37.

I The above reversal of pole-changer L will cause the switch A to bemovedaway from the obstruction so that a second trial to move the switchagainst theobstruction may be attempted. Y

The design of relay T and particularly the positioning of roller 35 withrespect to arm 37 issuch that-an appreciable time interval is required Ifor operation of relay T in the presence of an overload, but the relaywill restore itself in a very short interval which is only a fraction ofthe time required for operation. This result is obtained because roller35 must travel a substantial distance before arm 37 will be released buta small return movement of roller 35is suflicient for latching arm 37against roller 35.

vIt will be apparent, therefore, that the time which the operatormust/wait beforereversing pole-changer L after an overload has occurredis very short and is therefore not objectionable from a practicaloperating standpoint. i While I have illustrated motor control apparatusembodying my invention as applied to the control of a motorfor'operating a railway switch, it will be readily understoodthat'apparatus embodying my invention is not limited to this use, butmay be applied to the control ofany motor for operating any movabledevice- Although I have .herein shown and described only one form ofmotor. control apparatus embodying my invention, it is understood thatvarious changes and modifications may be made therein within the scopeof the appended claims invention.

Havingthus described my invention, what I claim is: p p g 1 1. Incombinatiom an electro-responsive device, a circuit for energizing saiddevice including a normally closed'contact, two windings for withoutdeparting iromthe spirit and scope of my governing said contact, meansresponsive to the magnitude of the current received by said device,

and a governingcircuit forrsaid. windings controlled by said means insuch manner that said windings aid one another when said current is,below'a predetermined value whereby saidcon-iv tact remains closedbutthat said windingsoppose one another when said current exceedsapredetermined value whereby said contact becomes opened.

2.In combination, an electro-respons'ive deviceftwowindings, means forcausing said deand for energizing said windings in series when saiddevice receives current exceeding a'prede termined value.

3; In combination, an electro-responsive device, a magnet comprising twowindings capable of assuming one or another of two conditions accordingas said windings are energized in parallel or in series with each other,means for controlling said device in accordance with the condi-,

tion of said magnet, and means responsive to the magnitude of thecurrent supplied to said device for energizing said windings in parallelor in series according as said current is below or above a wpredetermined value.

4. In combination, an electro-responsive device, a controller comprisinga magnetizable core in which a plurality of fluxes can be established insuch manner as to aid or oppose each other, means for governing saiddevice according as said fluxes are aiding or opposing, and meansincluding a plurality of windings on said controller for establishingaiding or opposing fiuxesin said core according as the current receivedby said device is below or above a predetermined value.

5. Incombination, an electric motor comprising an armature, a first anda second winding connected in series across said armature, means forsupplying current to said armature in accordance with one or another oftwo conditions effective when said first and second windings receivecurrent in parallel or in series with each other, respectively, andmeans responsive to the magnitude of the current supplied to saidarmature for causing said first and second windings to receive currentinparallel with each other if said armature current is below apredetermined value and for causing said firstand second windings to receive current in series with eachother if said armature current exceedsa predetermined value. 6. In combination, a movable device,,an electricmotor for operating said device, two windings capable of assuming one oranother of two conlel or in series with each other according as themotion of said movable device is freeor obstruct ed, and means forgoverning said motor inaccordance with the condition of said windings-7. In combination, an electro-responsive device, a circuit forenergizing said device includinga normally closed contact, two windingsfor governing said contact, means responsive to-the magnitude of thecurrent supplied'to said device for causing the fluxes set up by saidtwo windings to substantially neutralize one another if saidcurrentexceeds a normal value, and means for causing said contact to-open whensaid fiuxes are substantially neutralized.

CLARENCE W. DALZELL.

